7 Frequency of five CFTR gene mutations in miscegenated cystic fibrosis population of the Brazilian Northeast

Abstract

Introduction There are more than 1,900 known mutations in the CFTR gene. In the state of Bahia, in the northeastern area of Brazil, there are high rates of miscegenation, principally white/black miscegenation. The knowledge about genetics of cystic fibrosis (CF) in this population is scarce. Objective To determine the prevalence of five CFTR gene mutations in cystic fibrosis patients being assisted at Professor Edgard Santos Teaching Hospital in Salvador, Brazil. Methods It was a cross-sectional study involving 47 patients of 0–20 years of age with cystic fibrosis. The molecular analysis for DF508, G542X, G551D, R553X and 3120+1G→A mutations was performed by standard methods. Results The median age of the patients was 5.6 years at the time of diagnosis. The allele frequency of DF508 and G542X mutations was 23.9% (21/88) and 2.7 (2/74), respectively. So far the mutations G551D, R553X and 3120+1G→A have been studied in 21 patients. Three patients had the splicing mutation 3120+1G→A and the other mutations were not observed. Conclusion The diagnosis of the disease was late. The frequency of the DF508 mutation was lower than that one found in Caucasian populations, but the frequency of G542X mutation was similar to the one observed in this population. The 3120+1G→A mutation was found in three patients.